Semiconductor devices are often fabricated through multiple processes using different process tools. For example, ion implantation is a very complex and widely used process in the manufacture of integrated circuit devices. Ion implantation often involves incorporating dopant materials (e.g., arsenic or boron) into a wafer (e.g., a substrate) to form implant regions having a certain dopant concentration and profile. Usually, ion implantation processes are performed on a group or a batch of wafers. The number of wafers processed in each batch may vary depending on the ion implant tools used to perform the process.